1. Field of the Invention
The present invention relates generally to a liquid purifying porous filter, and a liquid purifying filter assembly and a liquid purification plant employing the same for removing organic and inorganic impurities, harmful contaminants, offensive odor substances and the like from a liquid containing those substances. More specifically, the invention relates to a high performance and a high capacity liquid purifying filter, and a liquid purification filter assembly and a liquid purification plant for obtaining a purified drinking water or a purified water from water contaminated with organic and/or inorganic substances or so forth, such as water of a water service, in the river, the sea, a pool, a drainage or so forth, and for obtaining a beer, a wine, a sake, a soy sauce, a sauce, a drink, a fruit juice, a cooking oil and so forth by filtering various solids and impurities.
2. Description of the Related Art
Conventionally, there have been proposed and used filtration plants employing porous ceramic filters as filtering members for filtering out various contaminants, bad smell (offensive odor) substances and impurity not suitable for drinking, in order to obtain a drinking water from water in the river, the sea or drainage. Also, in the recent years, water purification equipments have been available in the market, which improves bad smell and/or poor taste of a well water or a city water due to small content of organic and/or inorganic substances or so forth. Many of such water purification equipments also employs the porous ceramic filters.
Furthermore, for removal of solids and/or impurities from fermentation products in brewing of a beer, a wine, a sake, a soy sauce or the like, or for removal of solids and/or impurities to obtain a sauce, a drink, a fruit juice, a cooking oil and so forth from food materials, the porous ceramic filters are also used. Since the drinking water, liquors, fruit juices, drinks, cooking oils are served for drinking and eating, substantially high performance is required as the performance of the purification equipments. Also, in case of implementation in the industrial scale, large scaling of the purification plant becomes necessary.
On the other hand, due to recent increased sensitivity for environmental pollution, requirements for water quality for industrial waste is becoming more strict. This induces requirement for higher performance and larger scale of purification plants for water purification. In addition, it is a trend toward the future to apply restriction even for waste from various businesses, waste from school, various facilities and so forth, waste from families, living originated waste. Due to such prospect, high performance and low cost purification equipments in various types in a wide range of scales from small one to large one have been required.
In the meanwhile, associated with recent growth of interests for physical fitness, various people, irrespective of age and sex, enjoy swimming in the pool as a whole body exercise which promotes health and reduces stresses.
With the desire for further enjoying swimming in safer and more healthy environments, sensitivity for sanitary condition of the pool, particularly for water quality is growing. For this reason, demands for the purification plants which determine water quality of the pools become more severe. In response to such demands, progress has been made higher performance and larger scale in the purification plants.
Here, further discussion will be given with taking a pool water purification plant as a typical example. The pool water purification plant generally includes a pre-filtration unit for removing impurities, such as dirt, hairs and so forth, a filtration unit, an absorptive purification unit, a disinfecting unit for implementing disinfecting of the pool water, and so forth. In addition, a unit for supplying a filter aid for the filtration unit, a pool water heating unit in case of a warm water pool or so forth may be incorporated as required. Normally, the pool water is purified by circulation between this purification plant and the pool and thus maintained in sanitary condition.
In such circumstance, the porous ceramic filters are frequently employed as the filtration unit applied for the pool water purification plant. The porous ceramic filter has three-dimensionally arranged fine filtration void network suitable for trapping or filtration of the water in the pool, particularly in the warm water pool. The porous ceramic filter enables satisfactory filtration even for the organic substances, such as oils excreted from the human body, which cannot be filtered out by the conventional filters.
FIG. 24 generally shows the conventional pool water filtration unit employing such porous ceramic filter. In the conventional filtration unit, a cylindrical porous ceramic filter (hereafter referred to as "filter") 500 is closed by a lid 502 at the top and is fixedly disposed within a hollow cylindrical housing tank 504. Typically, in the pool water filtration unit, a plurality of filters 500 may be fixed within the tank depending upon an amount of pool water to be processed, a capacity of the tank and so forth. However, the exemplary example of the filtration unit as a typical example, illustrates an example employing one filter 500 within the tank 504.
An inlet line 508 for introducing water from a pool 506 is connected to the side wall of the tank 504 at the left side in the drawing. An outlet line 510 for recirculating the purified pool water to the pool 506 is connected to the center of the bottom of the tank. Also, a line 512 for introducing a filter aid is arranged in the side wall at the right side in the drawing. An air vent 514 is provided at the top surface of the tank. Furthermore, a drain line 516 is arranged outside of the filter 500 in the bottom of the tank. In addition, a back wash line 518 for washing the filter 500 is connected to the outlet line 510. By a circulation pump 520, the pool water is circulated from the pool 506 through the inlet line 508, the filtering tank 504 and the outlet line 510 in order and then recirculated into the pool. Namely, the pool water is pressurized to pass the filter 500 as indicated by the solid arrows so that the impurities can be removed by the filter 500, and the purified water is then recirculated into the pool 506.
In the meantime, the porous ceramic filters generally performs fine filtration and thus have high filtration performance. However, in the shown conventional cylindrical porous ceramic filter 500, the processing performance is limited. Therefore, in the filtration unit for the drinking water, liquors and so forth, or the pool water, a plurality of filters 500 are fixedly disposed within the filtration tank for obtaining necessary processing performance. As a result, the high performance filtration unit inherently becomes large.
In addition, the pool water purification plant includes a plurality of components, such as foregoing various types of pre-filter units depending upon the object, various disinfection units, absorptive filter units and so forth, in addition to the filtration unit. Piping for connecting these components becomes complicate to further increase the size of the overall construction of the purification plant.
Conversely, for efficient use of the pool, increasing of utility facilities and limitation of the construction area of the facility, the pool water purification plant is often required to be installed in a relatively narrow limited space. The same is true of the purification plants for drinking water, liquors, liquidous seasonings or so forth. For this reason, a liquid purification plant employing a high performance and compact porous ceramic filter has been desired.